How to Test a Central Heating Pump (Expert Guide)
Central heating failures are often not due to the boiler itself but to peripheral components such as pumps and motorised diverter valves. These are among the few moving parts in the system and are more likely to be subject to wear and failure over time.
But if this is the first time your central heating has failed, or you’ve never worked with a central heating pump before, you probably have a few questions.
“How does a central heating pump work?” ... “Where is my central heating pump?” … and “How do I check that the central pump is working?”
To help you identify the potential issue with your central heating system, and save you the expense of having your pump serviced, we’ve spoken to our in-house engineers. With over 40 years of experience in the industry, they’ve helpfully listed a simple guide to testing your central heating pump.
Where is my central heating pump?
The central heating pump will usually be located near to the boiler or the hot water cylinder in non-combi systems. It’s also worth checking to the rear of an airing cupboard. In older houses, central heating pumps can also be located under floorboards. In this case, you will need to remove the carpet and look for any loose or removable floorboards.
How to check if a central heating pump is working?
If your central heating system has failed and you suspect that the central heating pump is not working, follow our 9 step guide to testing a central heating pump below. These steps are for Lowara and Grundfos pumps, but will generally apply to all central heating pumps.
Step 1: Find the Pump
First of all, find it - the pump will usually be located near to the boiler or the hot water cylinder in non-combi systems. It will generally be made by Grundfos or Lowara and will have the maker's name on it.
Step 2: Visibly inspect the pump for damage
Pumps are usually cylindrical in design and will often have a switch allowing the flow rate to be adjusted. If you think you have a problem with your pump, try lightly touching it. If it's working properly there will be a slight vibration and it will be warm to the touch.
Step 3: Turn off the power supply
If your pump isn't working, turn off its power supply and get a cloth and a screwdriver.
Step 4: Loosen the silver plate
In the centre of the pump, you'll see a silver plate with a slot in it. Loosen this by half a turn - be careful here, as the pump could be full of hot water. You should get a slight hiss as air escapes and some water will drip out - that's why you need the cloth.
Step 5: Remove the silver plate
If the water is cool enough, remove the silver plate. Be careful not to lose it.
Step 6: Check if the pump shaft has seized
Once the silver plate is removed, you should then be able to see the end of the pump shaft, which has a small slot in it. This should turn easily with a small screwdriver. If it doesn't then it's seized, and you'll need to replace the pump.
Step 7: Turn the power back on
If the shaft turns easily, turn the power back on. If you can see the shaft spinning but you're still not getting heat, then it's likely the problem is air in the system or the impeller has broken.
Step 8: Bleed the system
If you suspect the problem is air in the system you will need to bleed the pump. Most central pumps usually have a bleed valve, but make sure you bleed the rest of the system too, including radiators.
Step 9: Check for a broken impeller
A broken impeller will usually lead to a rattling or clicking noise as the fragments float around inside the pump. If this is the case, the pump will need replacement. You can find products from Anchor Pumps to help with any central heating pump issues.
If you’re struggling with your central heating pump, read our dedicated guide to common central heating pumps here: https://www.anchorpumps.com/blog/the-complete-guide-to-central-heating-pump-problems-and-how-you-can-fix-them/
Best central heating pumps under £150
If the pump shaft has seized, then you will more than likely need to replace the pump. To help you replace the broken pump, we’ve listed the three best central heating pumps under £150.
If the pump was installed less than 5 years ago, make sure to check your manufacturer warranty, you may be able to replace the pump under warranty.
Grundfos UPS Domestic Heating Pump
The Grundfos UPS is one of the most popular domestic heating pumps on the market. Complete with modern motor technology and electronic control, the UPS offers the quality engineering of Grundfos at only £79.00. If you’re looking for a trustworthy pump that is simple to use and likely to last well over 15 years, then the UPS is ideal.
Price - From £79.00
House - 2 - 4 bedroom house
Search Prices on the Grundfos UPS 15 - 60 here.
Lowara Ecocirc Domestic Circulator
Did you know that nearly a third of your energy bills over the winter period is caused by a central heating pump? Yeah, it’s true. Fortunately, the Lowara Ecocirc is the most energy-efficient pump on the market. Helping you keep electricity bills to a minimum, the Lowara Ecocric range offers an abundance of advanced technological design that reduces the amount of electricity needed to pump water. An advanced, simple-to-use pump, that will surely become a popular choice among plumbers.
Price - From £96.00
House - 2 - 5 bedroom house
Search Prices on the Lowara Ecocirc pump here.
DAB Evosta Central Heating Pump
For a pump that has some real muscle at an affordable price, you need to check out the DAB Evosta range. Costing only £65.00, the DAB Evosta is the only pump we would trust to work efficiently for 10 plus years at below £70. Offering all the standard circulator technology, the DAB Evosta is an ideal choice for the family on a budget.
Price - From £65.00
House - 2 - 4 bedroom house
Search Prices on the DAB Evosta here.
Contact Anchor Pumps
If you’re struggling for advice, call our dedicated pump experts for free advice on: 0800 112 3134 or 0333 577 3134.
We’re open Monday to Friday 07:00 - 17:30 and Saturday 08:30 - 12:30.